Intraocular lenses (lOLs) are now the accepted treatment following cataract surgery in older children and are being used increasingly in younger children and infants, but little is known about the safety or efficacy of lOLs for a rapidly growin eye. The objective of the Infant Aphakia Treatment Study (lATS) is to compare the relative efficacy and safety of lOL correction versus contact lens correction in infants with a unilateral congenital cataract removed between the ages of 1 to 7 months. The primary outcome of the clinical trial is visual acuity. We enrolled 114 patients in lATS between December 2004 and January 2009. Phase 1 of the lATS involved following all patients to one year of age so that grating acuity could be assessed with Teller Acuity cards and was completed in January 2010. Phase 2 of lATS involved following all patients to 5 years of age and assessing optotype acuity with the HOTV test at age 4 years. We are now requesting additional funding to perform one more clinical examination of these patients at age 10 years so that the following factors can be compared between the two treatment groups: 1) the primary outcome, visual acuity using the E-ETDRS logMAR chart; and 2) the incidence of glaucoma after a longer-term follow-up. The public health importance of this clinical trial not only impacts the approximately 400 children born each year in the United States with a unilateral congenital cataract, but also the 200,000 children worldwide who are blind from cataracts. lATS is funded through two grants, one for the Chairman's Office (U10 EY013272, Scott Lambert, PI) and one for the Data Coordinating Center (U10 EY013287, Michael Lynn, PI).